Heretofore, it is known to use a porously textured resin film in order to deaerate gases from treating water, supply water for piping, operating oil, coating solutions, and so on in boilers, pure water manufacturing equipment and so on.
To this end, there has been adopted, for example, a film material, such as porous cellulose acetate, polyamide resin, polytetrafluoroethylene resin, which is supported in a spiral shape, in a tubularly wound shape, in a flat plate shape (in a pressure-resistant plate shape) or the like, by a support body in a porous sheet.
Although it is noted as a matter of course that such conventional deaerating films can remove gases contaminated within a liquid, the films cause a large quantity of vapor to penetrate therethrough and to be discharged from the liquid, together with target gases, when they are used at liquid temperatures as high as 30.degree. C. or higher or at such a high-vacuum condition as exceeding the vapor pressure of the liquid. Therefore, in this case, a stroke volume of a vacuum pump to be used for deaeration should become remarkably large and the liquid to be treated is required to be cooled to a temperature as low as 30.degree. C. or below. Furthermore, a quantity of the liquid obtainable by deaeration is caused to be reduced by such treatment. Accordingly, the conventional deaerating methods are said to be disadvantageous from a standpoint of equipment or running operation.